Is the Principle of Relativity different for different theories?

In summary, according to the first paragraph, laws of transformation are needed so that a theory which describes a phenomenon w.r.t. one reference frame could be applied to explain the same phenomenon w.r.t. another reference frame. For Galilean transformation, acceleration is invariant. So, does it mean that the following statement: "Acceleration is invariant under Galilean transformation ." is a principle of relativity for Newtonian dynamics?
  • #1
Pushoam
962
51
ap1.png

ap2.png
The images have been taken from the section : Relativity according to Galileo and Newton, page no.66, special relativity , A.P.French,1968What I understood is:
According to the first paragraph,
Laws of transformation are needed so that a theory which describes a phenomenon w.r.t. one reference frame could be applied to explain the same phenomenon w.r.t. another reference frame.

Does it mean that Laws of transformations are different for different theories?A physical statement of what these invariants are is called a principle of relativity.
For Galilean transformation, acceleration is invariant.
So, does it mean that the following statement:
"Acceleration is invariant under Galilean transformation ."
is a principle of relativity for Newtonian dynamics.
So, for different theories , there will be different principle of relativities. Right?

Fundamental equations of theory usually defines the principle of relativity applicable to the theory.
e.g.
The equation F = ma defines the principle of relativity, i.e. force in Newtonian Dynamics.
 
Physics news on Phys.org
  • #2
Pushoam said:
Does it mean that Laws of transformations are different for different theories?

Yes. For example, Newtonian mechanics uses Galilean transformations, whereas special relativity uses Lorentz transformations. And since the actual transformation laws obeyed in experiments can be tested, we can show experimentally that the Newtonian transformation laws are wrong and the special relativity transformation laws are correct.

Pushoam said:
for different theories , there will be different principle of relativities

Yes.

Pushoam said:
"Acceleration is invariant under Galilean transformation ."
is a principle of relativity for Newtonian dynamics

Pushoam said:
The equation F = ma defines the principle of relativity, i.e. force in Newtonian Dynamics

These I'm not sure about. I would expect the principle of relativity applicable to a given theory to be defined simply by the transformation laws themselves, not necessarily consequences of them.

Or, if one is going to define the principle of relativity for a given theory in terms of invariants, I think one would have to be able to use the invariants to uniquely determine the transformation laws. This works for special relativity, since the Lorentz transformations are the unique ones that preserve the relevant invariants (the speed of light and spatial isotropy). I'm not sure if it works for Newtonian mechanics if we take the relevant invariants to be acceleration and spatial isotropy--that is, I'm not sure the Galilean transformations are the unique ones that preserve those two invariants.
 
  • Like
Likes Pushoam
  • #3
Assuming that the principle of inertia is valid, i.e., that there exists a class of reference frames, the inertial frames, where a free particle moves with constant velocity, for which for any observer at rest relative to an inertial frame time and space are homogeneous and space is isotropic and that the set of symmetry transformations forms a Lie group you find that there are, up to equivalence, only two spacetime manifolds fulfilling these properties, namely the Galilean spacetime and the Minkowski spacetime.

For details, see e.g.,

V. Berzi and V. Gorini, Reciprocity Principle and the Lorentz Transformations, Jour. Math. Phys. 10, 1518 (1969)
http://dx.doi.org/10.1063/1.1665000
 
  • Like
Likes Pushoam
  • #4
The Galilean and Minkowski spacetimes are flat, hence is makes sense to ask a different question: How are two frames of references A,B connected (thus by which transformations of variables), so that the motion of object O in reference frame A which is along a straight line is mapped into the motion of the object O in reference frame B which is also along a straight line? The answer you can find here: http://www.mathpages.com/home/kmath659/kmath659.htm.
 
  • Like
Likes Pushoam

1. What is the principle of relativity?

The principle of relativity states that the laws of physics are the same for all observers in uniform motion, regardless of their relative velocity. This means that there is no preferred frame of reference in the universe.

2. Who first proposed the principle of relativity?

The principle of relativity was first proposed by Albert Einstein in his theory of special relativity in 1905.

3. What is the difference between special relativity and general relativity?

Special relativity deals with the laws of physics in inertial frames of reference, while general relativity extends these laws to non-inertial frames and includes the effects of gravity.

4. How does the principle of relativity impact our understanding of time and space?

The principle of relativity has led to the concept of time dilation, where time passes at different rates for observers in relative motion. It also introduced the idea of spacetime, where space and time are interconnected and can be affected by gravity.

5. What evidence supports the principle of relativity?

One of the key pieces of evidence for the principle of relativity is the Michelson-Morley experiment, which showed that the speed of light is constant in all frames of reference. Additionally, many experiments have confirmed the predictions of special and general relativity, including the famous Eddington eclipse expedition that confirmed the bending of light by gravity.

Similar threads

  • Special and General Relativity
5
Replies
144
Views
6K
  • Special and General Relativity
Replies
8
Views
204
  • Special and General Relativity
Replies
8
Views
1K
  • Special and General Relativity
Replies
29
Views
2K
  • Special and General Relativity
Replies
5
Views
2K
  • Special and General Relativity
Replies
11
Views
1K
  • Special and General Relativity
Replies
7
Views
1K
  • Special and General Relativity
Replies
9
Views
936
  • Special and General Relativity
Replies
21
Views
991
  • Special and General Relativity
Replies
7
Views
1K
Back
Top